1906

EDN1

endothelin 1;EDN1;endothelin 1

endothelin-1|preproendothelin-1

6p24.1

protein-coding

Endothelin-1[ET-1] acts as a growth factor in various malignancies. Big endothelin-1 (big ET-1) is the precursor of ET-1. The aim of this study was to determine the importance of serum big ET-1 levels as a novel marker of disease in female patients with breast cancer of various clinical stages. The study consisted of 75 female patients with breast cancer who were diagnosed and treated at the Gazi University Department of Medical Oncology and 20 controls. The patients were classified as follows: group A [n=26], patients with newly diagnosed primary breast cancer but without metastasis; group B [n=33], patients with metastatic breast cancer who had undergone treatment for their diseases and in whom metastasis was detected during follow-up; group C [n=16], off-therapy patients whose cancer had been in remission for at least 5 years; and group D [n=20] healthy controls. Serum big ET-1 level were measured with an enzyme immunoassay kit. The median serum big ET-1 levels of the 75 patients with breast cancer [10.96+/-1.36 ng/ml] were statistically significantly higher than those of controls [8.97+/-1.55 ng/ml]. The median serum big ET-1 levels of the patients with primary breast cancer patients [group A] were statistically significantly different from those in the controls, the off-therapy patients and the patients with metastatic disease [11.56+/-0.78 ng/ml, 8.97+/-1.55 ng/ml, 9.76+/-1.52 ng/ml, and 10.83+/-1.18 ng/ml respectively, P=.001]. There was no statistically significant difference in the serum big ET-1 levels of patients in group A in terms of tumor stage, hormone receptor status or lymph node status. Serum big ET-1 levels were statistically significantly higher in patients with metastatic disease than in controls or off-therapy patients (P=.001). The serum big ET-1 levels of off-therapy patients whose disease was in remission were not statistically significantly different from those in controls (P>.05). Serum big ET-1 levels seemed to represent the activation of ET-1 in female patients with breast cancer. Serum big ET- 1 levels can be an indicator of the breast cancer. Further studies are needed to demonstrate the prognostic importance of serum big ET-1 in patients with breast cancer.

OBJECTIVE: To evaluate the expression of endothelin-1(ET-1) and matrix metalloproteinase-9 (MMP-9) in laryngeal carcinoma and their correlations with clinical features. METHOD: The expression of ET-1 and MMP-9 was detected by immunohistochemical method in 58 specimens of laryngeal carcinoma, 28 specimens of polyps of vocal cord and 19 specimens of normal laryngeal tissues. RESULT: The expressions of ET-1, MMP-9 in laryngeal carcinoma were remarkably higher,compared to polyps of vocal cord and normal laryngeal tissues (P < 0.05). The expression of ET-1, MMP-9 was associated with clinical stage, T stage and lymph node metastasis. expression levels of ET-land MMP-9 correlated significantly with each other (r(s) = 0.693, P < 0.05). CONCLUSION: The expression of ET-1 and MMP-9 may be the vital indexes in laryngeal carcinoma.

Melanoma cell adhesion molecule (MCAM) is a cell-surface adhesion molecule expressed on over 70% of metastatic melanoma cells but not expressed in normal melanocytes invivo. Protein levels of MCAM correlate with aggressive invasive behavior of melanoma cells in vitro and invivo. Here we demonstrate that endothelin-1 (ET-1) upregulates MCAM protein in primary human melanocytes. MCAM upregulation by ET-1 occurs irrespective of degree of melanocyte pigmentation and is dose-responsive. The drug BQ788 is an endothelin-B (ET(B)) receptor antagonist and inhibits upregulation of MCAM by ET-1. In addition, endothelin-3 (ET-3) and N-succinyl-[Glu9, Ala11, 15]-ET-1-1620, both selective ET(B) agonists, are potent upregulators of MCAM. These demonstrate a critical role for the ET(B) receptor in the upregulation of MCAM by ET-1 and related isoforms. MCAM mRNA abundance is also increased by ET-1 stimulation, thus the mechanism of MCAM protein upregulation may occur at the level of transcription. Our previous studies have demonstrated that ET-1 downregulates E-cadherin in melanocytes and melanoma cells. Since E-cadherin is a melanoma invasion suppressor, and MCAM is a melanoma invasion promoter, ET-1 may promote melanoma invasion and metastasis through the regulation of adhesion molecule expression.

The endothelin pathway plays a critical role in melanoma tumor progression by a variety of mechanisms that enhance tumor cell growth, invasion, and metastasis. Here, we investigate the effect of this pathway on CXC chemokine expression in human melanoma cells and melanocytes. As determined by ELISA, endothelin-1 (ET-1) induces CXCL1 and CXCL8 secretion in three human melanoma cell lines in a concentration-dependent fashion. These responses are mediated by the endothelin-B receptor and are sustained over a 40 h time course. ET-1 does not induce CXCL1 secretion in primary human melanocytes but ET-3, an endothelin isoform, induces a low level of CXCL1 secretion in certain cultures. Neither ET-1 nor ET-3 induces secretion of CXCL8 in primary human melanocytes; thus, this response may be specific for melanocytic cells that have undergone malignant transformation. We have previously demonstrated that ET-1 induces changes in the expression of adhesion molecules in melanoma cells such that invasion and metastasis are favored. This study demonstrates that ET-1 additionally induces secretion of CXC chemokines critical for melanoma metastasis and tumor progression.

Endothelin receptor B (ET(B)R) is a G-protein-coupled receptor overexpressed in melanoma, blood, and lymphatic endothelial cells. Given that aberrant signal transduction can be mediated through cross talk between receptors, here, we explore the functional relationship between ET(B)R and the vascular endothelial growth factor receptor (VEGFR)-3 system and how this cross talk might influence the aggressive behavior of melanoma cells. The expression of VEGFR-3 and its ligands, VEGF-C and VEGF-D, significantly increased after activating ET(B)R by ET-1 in primary and metastatic melanoma cell lines. These effects, similarly to those induced by hypoxia, were mediated by hypoxia-inducible factor (HIF)-1alpha and HIF-2alpha. ET-1 caused the phosphorylation of VEGFR-3, which was accompanied by the activation of the downstream signaling molecules, such as MAPK and AKT. Inhibition of c-Src activity or silencing of the scaffold protein beta-arrestin-1 reduced ET-1-induced VEGFR-3 phosphorylation, demonstrating that, upon ET-1 stimulus, beta-arrestin-1 is involved with c-Src in the ET(B)R-mediated VEGFR-3 transactivation. Moreover, ET-1 in combination with VEGF-C further increased VEGFR-3, MAPK, and AKT phosphorylation and markedly promoted cell migration and vasculogenic mimicry. Dual inhibition of ET(B)R and VEGFR-3 was required for the effective inhibition of these effects, as well as for VEGFR-3 phosphorylation, demonstrating that ET(B)R cross talk with VEGFR-3 enhances cell plasticity and motility. Finally, in melanoma xenografts, ET(B)R antagonist inhibited tumor growth and the activation of the VEGF-C/VEGFR-3 axis, indicating that targeting ET(B)R may improve melanoma treatment acting directly or indirectly by impairing ET(B)R cross talk with VEGFR-3.

CONTEXT: Endothelin-1 (ET-1) plays a significant role in cancer biology and is considered as a potential target for molecular therapy. Alteration of ET-1 was detected in oral squamous cell carcinoma (OSCC). AIM: To evaluate the immunohistochemical expression and distribution of ET-1 in OSCC and to correlate its expression with the degree of histopathologic differentiation as well as the regional metastatic status of OSCC. MATERIALS AND METHODS: The immunohistochemical expression and distribution of ET-1 was evaluated in total number of 30 cases of OSCC. The specimens were retrieved as formalin-fixed, paraffin-embedded blocks from the archival files. Detection of ET-1 expression in different grades of metastatic and non-metastatic OSCC was quantified using an image analyzer computer system. STATISTICAL ANALYSIS USED: Statistical software package SPSS v. 19. RESULTS: ET-1 immunoreactivity was observed in all studied specimens. On comparing optical density values for ET-1 expression in different grades of OSCC, poorly differentiated OSCC showed a significantly greater expression than moderately differentiated OSCC, which was also significantly greater than well-differentiated OSCC ( P = 0.001). Moreover, ET-1 expression was higher in metastatic OSCC than that in non-metastatic OSCC ( P = 0.018). CONCLUSIONS: Increased ET-1 expression could enhance the aggressive behavior of poorly differentiated OSCC, especially metastasis. Accordingly, ET-1 could be a therapeutic target in OSCC.

Pulmonary metastases are the major cause of death of osteosarcoma (OS) patients. Endothelin-1 (ET-1) reportedly plays an important role in OS metastasis. In the present study, we for the first time explored the association of ET-1 SNPs with the risk of pulmonary metastatic OS. We genotyped three SNPs (rs1800541, rs2070699 and rs5370) in the ET-1 gene in a case-control study, using 260 pairs of age-, sex-, residence area- and tumor location-matched subjects. Patients with pulmonary metastatic OS and patients with localized high-grade (stage IIB) OS were enrolled as cases and controls, respectively. The G allele at rs1800541 was found associated with reduced risk of pulmonary metastatic OS after adjustment for body mass index, systolic blood pressure, diastolic blood pressure and the plasma ET-1 level (P=10(-4); adjusted OR, 0.55; 95% CI, 0.42-0.70), while the G allele at rs2070699 was not significantly associated with the risk of pulmonary metastatic OS (P=0.15; adjusted OR, 1.15; 95% CI, 0.87-1.50). The mRNA and the secreted protein levels of ET-1 in primary OS cell cultures (POCCs) established from surgically resected primary OS in the rs1800541 TT homozygotes were higher than those from the TG heterozygotes (P<0.05), who in turn showed higher ET-1 mRNA and secreted ET-1 levels than the GG homozygotes (P<0.05). In the control subjects, the rs1800541 TT homozygotes showed an 18.4% relapse rate, significantly higher than that of the GG homozygotes (0%) (P<0.01). On the other hand, the GG homozygotes showed a 71.4% complete recovery rate, significantly higher than that of the TG heterozygotes (7.3%) and the TT homozygotes (0%) (P<0.01). This study provides the first evidence of an association between the ET-1 gene SNPs and the risk of pulmonary metastatic OS.